wurtzite

Wurtzite is a hexagonal crystal structure type found in several compound semiconductors, most notably zinc oxide (ZnO), zinc sulfide (ZnS), gallium nitride (GaN), and beryllium oxide (BeO). It is one of the two common tetrahedrally coordinated, close-packed arrangements for these compounds, the other being the cubic zinc blende (sphalerite). In the wurtzite structure, atoms occupy positions in an ABAB stacking of hexagonal close-packed layers, leading to a three-dimensional network where each cation is tetrahedrally coordinated to four anions.

The structure belongs to the hexagonal crystal system with the space group P63mc. The ideal lattice is described by parameters a and c, with a typical c/a ratio around 1.633, reflecting the tetrahedral coordination. Wurtzite is non-centrosymmetric, which gives rise to piezoelectric and pyroelectric effects, making these materials useful in electromechanical and optoelectronic devices.

Many II–VI and III–V semiconductors crystallize in the wurtzite form under ambient or growth conditions; ZnO and GaN are prominent examples where the wurtzite polymorph is stable. ZnS also occurs in wurtzite as a natural and engineered phase, while zinc blende is another polymorph for several of these compounds. Under high pressure, some wurtzite materials transform to the rocksalt structure.

Wurtzite-based materials display properties attractive for optoelectronics, such as wide band gaps and strong piezoelectricity. ZnO and GaN, in particular, are used in light-emitting diodes, ultraviolet detectors, and nanoscale devices. Synthesis often employs vapor-phase methods or chemical routes that favor hexagonal stacking, including molecular beam epitaxy, chemical vapor deposition, and hydrothermal growth.